Horizontal production tree and method of use thereof

ABSTRACT

A horizontal production tree for use on a land-based surface well head. The horizontal production tree may be maintained in place on the well head throughout the life of well, even during fracing.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is based on and claims the benefit of U.S. Provisional Application Ser. No. 61/425,814, filed Dec. 16, 2010, which is herein incorporated by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention.

This invention relates generally to oil and gas well production trees, and more particularly to a horizontal production tree for use with oil and gas wells located on land.

2. Description of the Related Art.

Producing oil and gas wells frequently utilize production trees to control the flow of oil or gas out of the well. A production tree may also offer additional functions, such as chemical injection points, well intervention means, pressure relief means, tree and well monitoring points, and connection points for devices such as downhole pressure and temperature instrumentation.

Offshore oil and gas wells often utilize horizontal production trees. These offshore horizontal production trees are highly engineered and have many safeguards. The subsea type of offshore horizontal production trees are made to be operated by a Remotely Operated Vehicle.

However, horizontal production trees are not used on onshore surface wells. Rather, production trees for onshore surface wells typically have a vertical configuration. Such onshore vertical production trees must be removed from the well to frac the well and reinstalled when fracing is complete. Such removal and reinstallation can be expensive and dangerous and requires specialized machinery. Additionally, the production tree must be removed to run production tubing through and pull tubing out of the well. Furthermore, vertical production trees are large and difficult to repair without climbing, which is dangerous. Such large vertical production trees are also unsightly and undesirable in urban environments.

It is therefore desirable to provide a horizontal production tree that can be used on onshore surface wells. It is further desirable to provide a horizontal production tree for use with onshore surface wells through which an operator may frac the well and run production tubing through the well without removing the horizontal production tree. It is further desirable to provide a horizontal production tree for use with onshore surface wells that has a compact design allowing for easy repairs and easy concealment from public view in urban environments.

SUMMARY OF THE INVENTION

In general, the invention relates to a horizontal production tree with a body with a body bore extending substantially vertically therethrough, where the body bore has an upper portion with a diameter, a middle portion with a larger diameter than the diameter of the upper portion, and a lower portion. A sloped shoulder may be located between the upper portion and the middle portion of the body bore. A flapper valve gate may fit snugly against the sloped shoulder to prevent fluid in the middle portion of the body bore from traveling to the upper portion of the body bore. An arm with a first end and a second end may be is connected to the flapper valve gate. A stern may be perpendicularly connected to the second end of the arm, such that rotating the stem causes the arm and the flapper valve gate to pivot between a closed position, where the flapper valve gate is flush against the sloped shoulder, and an open position, where the flapper valve gate is not in contact with the sloped shoulder, where the stem has a first end and a second end. A recess may be located in the body extending from the middle portion of the body bore, where the first end of the stem is rotatably mounted with the recess. A channel may be located in the body extending from the middle portion of the body bore, where the stem extends through the channel and exits the body, such that the second end of the stem is located outside the body. The horizontal production tree may be configured such that the horizontal production tree may be connected to a land-based surface well head by mounting the horizontal production tree atop the land-based surface well head such that the horizontal production tree is vertically aligned with and in fluid communication with the land-based surface well head.

One or more production valves may be in fluid communication with the body bore and extending horizontally from the body. A pressure gage may be in fluid communication with the body bore mounted atop the body via a nut and plug assembly, or a work flange may be in fluid communication with the body bore mounted atop the body via a nut and sealing mechanism with a frac valve in fluid communication with the work flange and mounted atop the work flange. A frac isolation sleeve may be located at least partially within the body bore when the frac valve is. in use.

The lower portion of the body bore may have a smaller diameter than the middle portion of the body bore, in which case a sloped shoulder may be located between the middle portion and the lower portion. The arm may be connected to the stem via a connector portion of the arm, where the connector portion of the arm runs along a common axis with the stem and has an internal bore into which the stem fits. The body may have a recess extending from the middle portion of the body bore, into which recess the arm may fit when the flapper valve gate is in the open position, such that the flapper valve gate may lie substantially vertically.

The stem may comprise a lower stem with an internal end and an external end, where the internal end is internally threaded and the external end is the first end of the stem, which is rotatably mounted within the recess in the body extending from the middle portion of the body bore; and an upper stem with an internal end and an external end, where the internal end is externally threaded and may be screwed into the internal end of the lower stem and the external end is the second end of the stem. A bearing race assembly may be integral to the lower stem near its external end, such that the bearing race assembly is located within the recess in the body. One or more additional bearing race assemblies, one or more thrust bearings, or both one or more additional bearing race assemblies and one or more thrust bearings may be placed on the lower stem adjacent the bearing race assembly such that the additional bearing race assemblies and/or thrust bearings are located within the recess in the body.

The second end of the stem may terminate in a flapper valve bonnet assembly. The flapper valve bonnet assembly may comprise: a flapper valve bonnet attached to the body, where the flapper valve bonnet has an internal bore and the stem extends through the internal bore of the flapper valve bonnet; a valve packing and a packing retainer attached to the flapper valve bonnet, where the packing retainer has an internal bore and the stem extends through the internal bore of the packing retainer; a stem adapter attached to the second end of the stem; a hand wheel attached to the stem adapter, where the hand wheel can be turned to turn the stem adapter and the stem and, resultantly, pivot the flapper valve gate between the open and closed positions; and a bearing cap attached to the flapper valve bonnet and surrounding a portion of the flapper valve bonnet, a portion of the valve packing, and a portion of the stem adapter such that the bearing cap bridges the gaps between those elements. Furthermore, a first locking flange may be attached to the bearing cap; one or more holes may be located in the first locking flange; a second locking flange may be attached to the hand wheel such that the second locking flange abuts the first locking flange; one or more holes may be located in the second locking flange such that the holes in the second locking flange may align with the holes in the first locking flange when the hand wheel is in a particular position; and a locking pin may be inserted through a hole in the first locking flange and a corresponding hole in the second locking flange to prevent the hand wheel from turning relative to the bearing cap.

A method of using a production tree on a land-based surface well head comprises the steps of: mounting a horizontal production tree, as described above, atop a land-based surface well head such that the horizontal production tree is vertically aligned with and in fluid communication with the land-based surface well head; turning the hand wheel until the flapper valve gate is in the closed position; performing tasks that require the flapper valve gate in the closed position; turning the hand wheel until the flapper valve gate is in the open position; and performing tasks that require the flapper valve gate in the open position. Monitoring the pressure in the horizontal production tree comprises: turning the hand wheel until the flapper valve gate is in the closed position; mounting a pressure gage atop the body of the horizontal production tree via a nut and plug assembly, where the pressure gate is in fluid communication with the upper portion of the body bore of the horizontal production tree; turning the hand wheel until the flapper valve gate is in the open position; and reading the pressure in the horizontal production tree as displayed on the pressure gage. Fracing the well while maintaining the horizontal production tree in place atop the well head comprises: turning the hand wheel until the flapper valve gate is in the closed position; mounting a work flange atop the body of the horizontal production tree via a nut and plug assembly, where the work flange is in fluid communication with the upper portion of the body bore of the horizontal production tree; mounting a frac valve atop the work flange; turning the hand wheel until the flapper valve gate is in the open position; inserting a frac isolation sleeve within the body bore spanning the horizontal production tree and the well head; and fracing the well. Removing an instrument mounted atop the horizontal production tree from the horizontal production tree comprises turning the hand wheel until the flapper valve gate is in the closed position and removing the instrument from atop the horizontal production tree.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side cut-away view of the horizontal production tree of the present invention;

FIGS. 2A and 2B are side cut-away views of the top of the horizontal production tree with the flapper gate in a closed and an open position, respectively;

FIGS. 3A and 3B are side cut-away views of the top of the horizontal production tree with the flapper gate in a closed and an open position, respectively, where the view is rotated 90 degrees from the view of FIGS. 2A and 2B;

FIG. 4 is a cut-away perspective view of the hand wheel, stem, and flapper gate elements of the present invention;

FIG. 5 is an exploded view of the stem of the present invention; and

FIG. 6 is a side cut-away view of the horizontal production tree of the present invention, shown with a work flange and frac valve mounted atop the horizontal production tree.

Other advantages and features will be apparent from the following description, and from the claims.

DETAILED DESCRIPTION OF THE INVENTION

The devices and methods discussed herein are merely illustrative of specific manners in which to make and use this invention and are not to be interpreted as limiting in scope.

While the devices and methods have been described with a certain degree of particularity, it is to be noted that many modifications may be made in the construction and the arrangement of the structural and functional details disclosed herein without departing from the spirit and scope of this disclosure. It is understood that the devices and methods are not limited to the embodiments set forth herein for purposes of exemplification.

Referring to the figures of the drawings, wherein like numerals of reference designate like elements throughout the several views, and initially to FIG. 1, a horizontal production tree 1 is mounted atop a standard practice well head 2. Production valves 3 may extend from a body 4 of the horizontal production tree 1. A body bore 5 may extend vertically through the body 4 of the horizontal production tree 1, allowing for the horizontal production tree 1 to fluidly connect to the well head 2 at its lower end. Fluidly connected via the body bore 5 to the upper end of the horizontal production tree 1 may be a nut and plug assembly 6. The nut and plug assembly 6 may remain flanged up during the life of the well unless the horizontal production tree 1 is damaged.

The nut and plug assembly 6 allows a user to connect a variety of instruments to the horizontal production tree 1 for varied purposes. For example, in FIG. 1, a pressure gage 7 is connected to the nut and plug assembly 6. This configuration is. used to monitor the pressure in the horizontal production tree 1. In FIG. 6, a work flange 8 is connected to the nut and plug assembly 6 with its own nut and sealing mechanism, with a frac valve 9 connected to the work flange 8. This configuration allows for fracing through the frac valve 9 without removing the horizontal production tree 1 from the well head 2. A frac isolation sleeve 10 may be placed within the body bore 5 spanning the horizontal production tree 1 and the well head 2 to protect the horizontal production tree 1 during fracing.

The body bore 5 may have an upper portion 11, a middle portion 12, and a lower portion 13, where the upper portion 11 has a smaller diameter than the middle portion 12 and the middle portion 12 has a larger diameter than the lower portion 13. A sloped shoulder 14 bridges the middle portion 12 and the lower portion 13, allowing for easy entry of tubing and tools through the body bore 5. A sloped shoulder 15 also bridges the upper portion 11 and the middle portion 12. A flapper valve gate 16 may fit snugly against the sloped shoulder 15 to prevent fluid from the well from traveling through middle portion 12 of the body bore 5 to the upper portion 11 of the body bore 5, and ultimately entering the nut and plug assembly 6. The flapper valve gate 16 may be made of polyteflon or other suitable material to form a seal against the sloped shoulder 15.

The flapper valve gate 16 may be connected to an arm 17, allowing the flapper valve gate 16 to pivot between a closed position, where the flapper valve gate 16 is flush against the sloped shoulder 15 and prevents all fluids from traveling through middle portion 12 to upper portion 11, and an open position, where the flapper valve gate 16 is not in contact with the sloped shoulder 15 and does not inhibit the travel of fluid from the middle portion 12 to the upper portion 11. The closed position is shown in FIG. 2A and the open position is shown in FIG. 2B. The middle portion 12 of the body bore 5 may have a recess 50 into which the arm 17 may fit when the flapper valve gate 16 is in the open position, allowing the flapper valve gate 16 to lie substantially vertically to minimize inhibition of fluid movement from the middle portion 12 to the upper portion 11.

The arm 17 may be connected to a stem 18, which may be substantially perpendicular to the arm 17, via a connector portion 19. The connector portion 19 of the arm 17 may run along the same axis as the stem 18 and may have an internal bore into which the stem 18 may fit. The stem 18 may be more clearly seen in FIGS. 3A and 3B, which show a portion of the horizontal production tree 1 rotated 90 degrees from FIGS. 1, 2A, and 2B. FIG. 3A shows the flapper valve gate 16 in the closed position, while FIG. 3B shows the flapper valve gate 16 in the open position.

The stem 18 may be formed from two parts: a lower stem 20 and an upper stem 21. The structure of the stem 18 may be more clearly seen in FIGS. 4 and 5. The connector portion 19 of the arm 17 may be secured to the upper stem 21 via one or more keys 25, which each fit within a slot 27 running latterly along the exterior of the upper stem 21, and one or more set screws 26. The upper stem 21 may terminate in an externally threaded end 22, which screws into an internally threaded end 23 of the lower stem 20. The upper stem 21 and the lower stem 20 may then be secured to each other via a set screw 24.

The end of the lower stem 20 opposite the internally threaded end 23 may be rotatably secured within a recess 28 in the wall of the middle portion 12 of the body bore 5. The lower stem 20 may have a bearing race assembly 29 integral to the lower stem 20, and additional bearing race assemblies 30 and thrust bearings 31 may be placed on the lower stem 20 adjacent the bearing race assembly 29.

The end of the upper stem 21 opposite the externally threaded end 22 may extend through a channel 32 in the wall of the middle portion 12 of the body bore 5 and terminate outside the body 4 of the horizontal production tree 1 in a flapper valve bonnet assembly 33. The flapper valve bonnet assembly 33 may comprise a flapper valve bonnet 34, which may be secured to the exterior of the body 4 via a plurality of nut and stud assemblies 35. The upper stem 21 may extend through an internal bore 36 in the flapper valve bonnet 34 and attach at its terminal end to a stem adapter 37 via a shear pin 38 extending through a hole 39 in the upper stem 21. A hand wheel 40 is attached to the stem adapter 37, whereby the hand wheel 40 can be turned to turn the stem adapter 37 and the stem 18 and, resultantly, pivot the flapper valve gate 16 between the open and closed positions.

A valve packing elastomer set may attach to the flapper valve bonnet 34 and also surround the upper stem 21. The valve packing is held in place by a packing retainer 45. A bearing cap 41 may surround a portion of the flapper valve bonnet 34, a portion of the packing retainer 45 and a portion of the stem adapter 37 such that the bearing cap 41 bridges the gaps between those elements. A first locking flange 42 may be attached to the bearing cap 41. The first locking flange 42 may have a plurality of holes located around its perimeter. A second locking flange 43 may be attached to the hand wheel 40 such that the second locking flange 43 abuts the first locking flange 42 when the flapper valve bonnet assembly 33 is fully assembled. The second locking flange 43 may have a plurality of holes located around its perimeter such that the holes in the second locking flange 43 may align with the holes in the first locking flange 42. A locking pin 44 may be attached to the hand wheel 40 via a connector 46 such that the locking pin 44 may be inserted through one of the holes in the first locking flange 42 and a corresponding hole in the second locking flange 43 to prevent the hand wheel 40 from turning, thus maintaining the flapper valve gate 16 in a particular position.

The horizontal production tree can be installed on a well and stay in place for the life of the well. The well operator can frac the well through the horizontal tree by using an isolation sleeve to get into the tree. This will allow the tree to be safeguarded from frac propellant and frac pressures. Keeping the production tree on the well saves the cost of having a service company remove and reinstall the production tree. Using the isolation sleeve in the tree saves cost on purchasing larger equipment to handle frac pressures. The operator can also run production tubing through and pull tubing out of the well with the horizontal production tree still on the well. The tubing can be run under pressure and removed with the tree on the well. There is no need to remove the horizontal production tree on workovers. BOPs and frac valves can be flanged up to the tree. Two mechanical barriers can be set within the horizontal tree if a lubricator is needed to change out equipment above the tree. The unique tubing hanger design of the horizontal production tree allows ease of entry into the tubing bore.

The horizontal production tree features a compact design. In field repairs can therefore be made without the need to climb on the equipment. Oil and gas operators may prefer the horizontal production tree in urban environments as its compact design allows for easy concealment from public view. The horizontal production tree can also be used in fields where the land owner uses irrigation sprayers, where height is an issue.

Whereas, the devices and methods have been described in relation to the drawings and claims, it should be understood that other and further modifications, apart from those shown or suggested herein, may be made within the spirit and scope of this invention. 

1. A horizontal production tree, comprising: a body with a body bore extending substantially vertically therethrough, wherein the body bore has an upper portion with a diameter, a middle portion with a larger diameter than the diameter of the upper portion, and a lower portion; a sloped shoulder between the upper portion and the middle portion of the body bore; a flapper valve gate, wherein the flapper valve gate may fit snugly against the sloped shoulder to prevent fluid in the middle portion of the body bore from traveling to the upper portion of the body bore; an arm with a first end and a second end, wherein the first end of the arm is connected to the flapper valve gate; a stem to which the second end of the arm is perpendicularly connected, such that rotating the stem causes the arm and the flapper valve gate to pivot between a closed position, wherein the flapper valve gate is flush against the sloped shoulder, and an open position, wherein the flapper valve gate is not in contact with the sloped shoulder, wherein the stem has a first end and a second end; a recess in the body extending from the middle portion of the body bore, wherein the first end of the stem is rotatably mounted with the recess; and a channel in the body extending from the middle portion of the body bore, wherein the stem extends through the channel and exits the body, such that the second end of the stem is located outside the body; wherein the horizontal production tree is configured such that the horizontal production tree may be connected to a land-based surface well head by mounting the horizontal production tree atop the land-based surface well head such that the horizontal production tree is vertically aligned with and in fluid communication with the land-based surface well head.
 2. The horizontal production tree of claim 1 further comprising one or more production valves in fluid communication with the body bore and extending horizontally from the body.
 3. The horizontal production tree of claim 1 further comprising a pressure gage in fluid communication with the body bore mounted atop the body via a nut and plug assembly.
 4. The horizontal production tree of claim 1 further comprising a work flange in fluid communication with the body bore mounted atop the body via a nut and sealing mechanism.
 5. The horizontal production tree of claim 4 further comprising a frac valve in fluid communication with the work flange and mounted atop the work flange.
 6. The horizontal production tree of claim 5 further comprising a frac isolation sleeve located at least partially within the body bore.
 7. The horizontal production tree of claim 1 wherein the lower portion of the body bore has a smaller diameter than the middle portion of the body bore, the horizontal production tree further comprising a sloped shoulder between the middle portion and the lower portion.
 8. The horizontal production tree of claim 1 wherein the arm is connected to the stem via a connector portion of the arm, wherein the connector portion of the arm runs along a common axis with the stem and has an internal bore into which the stem fits.
 9. The horizontal production tree of claim 1 wherein the body has a recess extending from the middle portion of the body bore, into which recess the arm may fit when the flapper valve gate is in the open position, such that the flapper valve gate may lie substantially vertically.
 10. The horizontal production tree of claim 1 wherein the stem further comprises: a lower stem with an internal end and an external end, where the internal end is internally threaded and the external end is the first end of the stem, which is rotatably mounted within the recess in the body extending from the middle portion of the body bore; and an upper stem with an internal end and an external end, wherein the internal end is externally threaded and may be screwed into the internal end of the lower stem and the external end is the second end of the stem.
 11. The horizontal production tree of claim 10 further comprising a bearing race assembly integral to the lower stem near its external end, such that the bearing race assembly is located within the recess in the body.
 12. The horizontal production tree of claim 11 further comprising one or more additional bearing race assemblies, one or more thrust bearings, or both one or more additional bearing race assemblies and one or more thrust bearings placed on the lower stem adjacent the bearing race assembly such that the additional bearing race assemblies and/or thrust bearings are located within the recess in the body.
 13. The horizontal production tree of claim 1 wherein the second end of the stem terminates in a flapper valve bonnet assembly.
 14. The horizontal production tree of claim 13 wherein-the flapper valve bonnet assembly further comprises: a flapper valve bonnet attached to the body, wherein the flapper valve bonnet has an internal bore and the stem extends through the internal bore of the flapper valve bonnet; a valve packing set and a packing retainer are attached to the flapper valve bonnet, wherein the packing retainer has an internal bore and the stem extends through the internal bore of the packing retainer; a stem adapter attached to the second end of the stem; a hand wheel attached to the stem adapter, wherein the hand wheel can be turned to turn the stem adapter and the stem and, resultantly, pivot the flapper valve gate between the open and closed positions; and a bearing cap attached to the flapper valve bonnet and surrounding a portion of the flapper valve bonnet, a portion of the valve packing, and a portion of the stem adapter such that the bearing cap bridges the gaps between those elements.
 15. The horizontal production tree of claim 14 further comprising: a first locking flange attached to the bearing cap; one or more holes in the first locking flange; a second locking flange attached to the hand wheel such that the second locking flange abuts the first locking flange; one or more holes in the second locking flange such that the holes in the second locking flange may align with the holes in the first locking flange when the hand wheel is in a particular position; and a locking pin, wherein the locking pin may be inserted through a hole in the first locking flange and a corresponding hole in the second locking flange to prevent the hand wheel from turning relative to the bearing cap.
 16. A method of using a production tree on a land-based surface well head, said method comprising the steps of: a) mounting a horizontal production tree atop a land-based surface well head such that the horizontal production tree is vertically aligned with and in fluid communication with the land-based surface well head, wherein the horizontal production tree comprises: a body with a body bore extending substantially vertically therethrough, wherein the body bore has an upper portion with a diameter, a middle portion with a larger diameter than the diameter of the upper portion, and a lower portion; a sloped shoulder between the upper portion and the middle portion of the body bore; a flapper valve gate, where the flapper valve gate may fit snugly against the sloped shoulder to prevent fluid in the middle portion of the body bore from traveling to the upper portion of the body bore; an arm with a first end and a second end, wherein the first end of the arm is connected to the flapper valve gate; a stem to which the second end of the arm is perpendicularly connected, such that rotating the stem causes the arm and the flapper valve gate to pivot between a closed position, wherein the flapper valve gate is flush against the sloped shoulder, and an open position, wherein the flapper valve gate is not in contact with the sloped shoulder, wherein the stem has a first end and a second end; a recess in the body extending from the middle portion of the body bore, wherein the first end of the stem is rotatably mounted with the recess; and a channel in the body extending from the middle portion of the body bore, wherein the stem extends through the channel and exits the body, such that the second end of the stem is located outside the body; b) operating the horizontal production tree atop the land-based surface well head.
 17. The method of using a production tree on a land-based surface well head of claim 16 further comprising the step of monitoring the pressure in the horizontal production tree by: turning the hand wheel until the flapper valve gate is in the closed position; mounting a pressure gage atop the body of the horizontal production tree via a nut and plug assembly, wherein the pressure gate is in fluid communication with the upper portion of the body bore of the horizontal production tree; turning the hand wheel until the flapper valve gate is in the open position; and reading the pressure in the horizontal production tree as displayed on the pressure gage.
 18. The method of using a production tree on a land-based surface well head of claim 16 further comprising the step of fracing the well while maintaining the horizontal production tree in place atop the well head, wherein fracing-the well further comprises the steps of: turning the hand wheel until the flapper valve gate is in the closed position; and mounting a work flange atop the body of the horizontal production tree via a nut and sealing plug mechanism, wherein the work flange is in fluid communication with the upper portion of the body bore of the horizontal production tree; mounting a frac valve atop the work flange; turning the hand wheel until the flapper valve gate is in the open position; inserting a frac isolation sleeve within the body bore spanning the horizontal production tree and the well head; and fracing the well.
 19. The method of using a production tree on a land-based surface well head of claim 16 further comprising the step of removing an instrument mounted atop the horizontal production tree from the horizontal production tree by: turning the hand wheel until the flapper valve gate is in the closed position; and removing the instrument from atop the horizontal production tree. 